FIELD OF THE INVENTION
This invention relates to a process for the production of shaped objects such as films, fibers and fabrics characterized by good antistatic properties, and also the use thereof in nonwoven materials. More specifically, this invention relates to two-component mixtures of polyesters with at least 5.1 wt. % polyol content derived from terpolymers comprising lactams, polyols and polyacyl lactams. The preferred range of polyol is 5.1 to 25%, and still more preferably 5.1% to 10% by weight, referred to the total composition in the composite article.
The production of fibers and fabrics with antistatic properties has long been an objective in the textile industry. However, many of the additives employed have had undesirable properties e.g. hygroscopicity, water extractability and stickiness. The present invention in providing a two-component polymeric melt blend makes it unnecessary to add an additive such as a metal salt since the desired antistatic effect is obtained directly from the said polymeric components.
The present invention includes fibers and other shaped articles such as films and cast objects, based upon the combination of a polyester such as polyethylene terephthalate together with the lactam terpolymers. The products of the invention are characterized by improved antistatic properties. The products acquire very little static charge and the static buildup is readily dissipated. This is a highly useful property in fabrics intended for various applications such as carpeting.
In order to prepare the desired polymeric compositions, the components are melt blended such as by grinding the individual polymers, and melting the fine powder or pellets or particles such as by charging the individual components to an extruder in which the components are melted in the screw of the extruder before being passed to a forming area such as a spinning area or a film forming area, or an injection molding area. A preferred embodiment is the spinning of the said melt blend into fibers. These fibers are highly useful per se and may be processed by conventional means such as texturizing and ultimately woven into fabrics.
One special embodiment of the invention is to provide fibers of anti-static, non-woven fabrics. In the following description the term "fibers" includes continuous filaments, staple fibers and yarns thereof. According to the invention, the melt blended fibers of a polyester and the lactam terpolymer can be bonded, e.g. thermally bonded to result in fabrics having integrity bonding.
The formation of a non-woven fabric from the discrete fibers is accomplished by calendering the fibers as a web between heated rolls, e.g., hot calendering 100.degree. C. to 210.degree. C. This may be carried out with a plain roll and a roll with a patterned surface. An appropriately patterned roll can be used to produce any desired pattern or heavy or primary bonded segments where the non-woven fabric is nipped between the rolls during calendering. If desired, both rolls may also be patterned to provide a desired design.